Chicken John converted his 1975 pickup truck to run on coffee grounds or walnut shells or pretty much any other trash you can burn. And not only does it run on trash, but it's a carbon-negative vehicle. Seriously. The truck itself is completely unmodified. Chicken just added a gasifier to it. It can run on gasoline with the flip of a switch. Gasification isn't some new-fangled technology. In Europe during World War II, over a million vehicles ran using wood burning gasifiers when gasoline and diesel were unavailable. The Cafe Racer: the car of yesteryear . . . today! How does it work? Watch the video below (click on the picture to start the video).

Gasification Overview
Basically it works like this: you burn stuff in a low-oxygen environment to extract hydrogen gas. You cool the hydrogen gas, filter it, and feed it into a regular gasoline engine. The engine doesn't know the difference, and it runs the same as if it was running on gasoline. There are several types of gasifiers. The Cafe Racer uses a stratified downdraft gasifier. This diagram shows the basic process.

For all of the technical details, see the links at the bottom of this page.

Gasifier Mileage
15 pounds of organic material is roughly equivalent to a gallon of gas. Chicken gets a ton of walnut shells (that's 2000 pounds) for 40 bucks. That's equivalent to 133.33 gallons of gas (or GGEs (gasoline gallon equivalents) in the alternative fuel lingo). That works out to 30 cents a gallon. The truck gets the same mileage on a GGE of walnut shells as it wood on a gallon of gas.

Emissions
The gasifier does emit some carbon dioxide--the same CO2 that would be released if the organic material decomposed in the dump. But gasification doesn't emit the methane that would be released during decomposition. Gasification also produces some carbon monoxide, water, tar, and charcoal.
But there's a way to make gasification carbon negative. The charcoal that is created during gasification is special. It's called bio-char. Because the low-oxygen fire in the gasifier doesn't burn up all of the wood, the bio-char retains a bunch of nutritious minerals that plants love, and it makes for a unique kind of fertilizer. The bio-char itself contains a lot of carbon that is kept out of the atmosphere, and using it as fertilizer helps plants and trees gather more carbon dioxide out of the air.

Possibilities for Large-Scale GasificationChicken John wants to build a big gasifier at the city dump to produce enough electricity to run MUNI. Ritual Roasters is working on creating a gasifier to power the coffee roaster at their new Bayview location. A coffee roaster powered by coffee grounds. How about that?
In the town of Güssing, Austria, they've got a big gasifier generator that produces 2 megawatts of electricity and 4 megawatts of thermal energy.
Out at Burning Man this year, Chicken's friend Jim Mason built a 100-foot long, gasifier-powered "slug" called the Mechabolic.
In addition to powering its engine using a gasifier, the Mechabolic also converts trash into a bio-diesel fuel using the Fischer-Tropsch process. It converts wet biomass (like food scraps) into a gas for fire effects on the Mechabolic using Anaerboic digestion. Jim is basically the mad genius behind this resurgence of gasification in the Burning Man community.

Learn More
Gasification still seems to be under the alternative-fuel radar, but it's picking up steam . . . err, picking up gas, I suppose. Gasification presents a fascinating contradiction: although the technology dates back some four thousand years to the invention of the forge, it hasn't developed much since the nineteenth century. Now, with the potential end of the oil age looming, a rag tag collection of scientists, engineers, artists, and freaks from around the world have realized the alternative fuel potential of gasification. They're working on bringing this forgotten technology into the 21st centruy. This batch of links is the tip of the melting iceberg: